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Red-throated Divers 270215
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Author:  Nige Lound [ Sun Mar 01, 2015 2:47 pm ]
Post subject:  Red-throated Divers 270215
On 27th February, whilst birding at Saltfleetby NNR I could see a few GC Grebe and RTDs on the sea from the end of Churchill Lane path and 15 RTDs went south so I walked to the tideline. Scanning 180 degrees from left to right I picked up 29 GC Grebe and 41 RTD on the sea, some close in. Scanning from right to left I counted similar again but then picked up a big flock of RTD moving south. I got to 100 and they still kept coming so I moved on the front of the flock and got an accurate count as they passed. The total single flock was an impressive 247. In total there were 314 with another 21 south and 5 north. I gave it another 15 minutes but very little moving after this for some reason. Where they came from and where they went is anybody’s guess.
I see that on the same date, Spurn had its 2nd ever highest count of RT Diver with 506 being logged.

Regards

Nige
Author:  Graham Catley [ Sun Mar 01, 2015 4:35 pm ]
Post subject:  Re: Red-throated Divers 270215
these mid winter one off movements of Red-throats as you say Nige seem a bit hard to fathom; Just dragged out my old record off Huttoft on January 6th 1980 when Mick Mellor and myself counted 521 Red-throats south in one and half hours after which as you say they suddenly stopped -- this though pales into insignificance compared to a count of Pacific Divers that we had off California on November 26th 1997 -- see below
Pacific Diver/Loon
The common diver offshore but only a few seen well in inshore waters most records being of flocks flying south from the coastal watchpoints. The largest concentrations noted were a huge southerly movement over at least 3 hours at Pigeon Point on 26th when specific counts showed birds moving past at a rate of 1000 in 5 minutes at their peak. On this date an estimated 20,000 passed this point and an additional 1000 were seen off Santa Cruz earlier in the day during strong onshore winds and heavy rain showers
Author:  Stephen Lorand [ Sun Mar 01, 2015 9:01 pm ]
Post subject:  Re: Red-throated Divers 270215
These late winter movements of Red-throated Divers tend to be sporadic and may possibly be food-related. In most years there is little evidence of any significant numbers. I have trawled through the Donna Nook logs and find that most winters produce maxima of low double figures. When high numbers have been encountered, they are usually in January and February, and only very occasionally in late December. I have never seen any exceptionally large autumn movements. Practically all large-scale passage at Donna Nook has been to the north, often in quite concentrated flocks and over short periods of time. In some instances, large flocks have been disturbed by boats, but these birds often fly only limited distances.
Rather than merely following the line of the coast, some of these birds do come in from a very long way out to sea. For example, 178 on 30th January 1969 did come in from the ESE and then turned to the north upon reaching the shore. The 1979/80 winter stands out as the best I have known for divers. Regular northerly movements began with 85 on 20th December followed by up to 52 daily until 5th January 1980 when 214 were recorded in 40 minutes. About 70 of these landed just offshore and joined a mass of feeding gulls, a record total of 13 Black-throated Divers, ca. 25 Guillemots , 4 Goosanders and a Great Crested Grebe.
Like Graham and Mick at Huttoft on the following day (6th January) we had our best ever diver day when between 0915 and 1300 515 flew north, plus 20 headed south and there were ca. 20 on the sea. This movement was further out than on the previous day and not all were specifically identified, but all positive sightings were Red-throateds. The count closely corresponded to the Huttoft figure, but passage was in the opposite direction. Later high counts that winter were 140 on 8th January, 260 on 22nd, 129 on 23rd January and 102 on 1st February, all heading north. My best count in more recent years was of 105 on 3rd January 2009.
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